Effect Of Metal Cations On The Montmorillonite Expansion And Stability

Clay minerals have a good property of dispersion in an aqueous solution,which could easily lead to pulp sludge and flotation mechanical entrainment or other issues affecting the grade and recovery of flotation concentrate.Meanwhile,the clay minerals in aqueous solution is difficult to settle,solid-liquid separation,which affect the water recycling.In this study for the purpose of the problem,we have studied the effect of metal cations on the montmorillonite swelling properties and dispersing properties,providing a theoretical basis for solving pulp sludge flotation and entrainment mechanical problems caused by the clay minerals.This study analyzes the effect of interlayer cations or electrolyte solution cations with different valence,different hydration properties to montmorillonite swelling properties and dispersion properties.In this study the effect of metal cations on the montmorillonite swelling properties have been explored though the layer spacing,capacity expansion,infrared analysis.The effect of metal cation with different valence or different hydration properties on montmorillonite suspension stability property have been explored under different conditions by montmorillonite suspension turbidity,degree of aggregation,determination of Zeta potential values and the calcium ion adsorption characteristics,additional the theoretical calculation method DLVO theoretical analysis.Prepared by ion exchange between the different layers of montmorillonite metal cations,results show that: there are differences between the different layers of metal cations of montmorillonite interlayer spacing and capacity expansion,the interlayer spacing in the order of Ca-MMT> Mg-MMT> Al-MMT> K-MMT> Fe-MMT> Na-MMT,the expansion capacity of the order of Na-MMT> Ca-MMT> Mg-MMT> K-MMT> Al-MMT> Fe-MMT.The results of swelling capacity under different conditions of electrolyte solution of metal cations show that: the higher of metal valence,the smaller expansion of montmorillonite content,the higher the degree of compression of the electrical double layer of montmorillonite.And for the same valency metal cation,the metal cation in the electrolyte solution,the better the water resistance,the higher the capacity expansion of montmorillonite,swelling properties,the better,the smaller the degree of compression of the electrical double layer of montmorillonite.Montmorillonite cohesion test results showed that: critical potential to aggregate as montmorillonite-23.5mV.For metal cations of different valence states,the ability to unite the size of a trivalent> divalent> monovalent,electrical double layer compression capability is also trivalent> divalent> monovalent.Agglomerative hydration ability of ion hydration better than the relatively poor ability of ions.Calcium montmorillonite surface adsorption studies showed that: calcium montmorillonite adsorption curve meets Freundich model,calcium ions adsorbed on montmorillonite is mainly based on ion exchange,adsorption and belongs advantage prone.To sum up,the type of the interlayer metal cation have interlayer spacing of montmorillonite and swelling of different effects,pH,the higher valence electrolyte ions,hydration properties worse,the higher degree of montmorillonite cohesion,dispersion worse.